Bipolar disorder i.e. manic-depressive illness is a cronic disease that affects about 1% of the population. The manic episodes contains symptoms of hyperactivity, insomnia, disorganized behavior, grandiosity and delusions often resulting in severe social impairment.
Lithium or a combination of neuroleptics and benzodiazepines are the most commonly used drugs for the treatment of acute mania (R. H. Gerner: Treatment of acute Mania. Psychiatr Clin North Am (1993) 16:443-460; P. Vestergaard: Treatment and prevention of mania: a Scandinavian perspective. Neuropsychopharm (1992) 7:249-259.).
However, the treatment is often not effective or endowed with various side effects.
Anticonvulsant drugs such as carbamazapine, valproic acid and lamotrigine have more recently proven efficacious as antimanic agents but their mechanism of action is still unclear.( J. Walden and B. Hesslinger: Bedeutung alter und neuer Antiepileptika in der Behandlung psychischer Erkrankungen. Fortschr Neurol Psychiat 63 (1995) 320-335.
P. E. Keck jr., S. L. McElroy and C. B. Nemeroff: Anticonvulsants in the treatment of bipolar disorder. J. Neuropsychiatry Clin Neuroscience (1992) 4:395-405 ).
Danish Patent no. 156398 discloses a class of compounds that exhibit .gamma.-amino butyric acid uptake (GABA-uptake) inhibitory properties and said compounds are valuable in the treatment of epilepsy and other related diseases.
The R-isomer of N-(4,4-di(3-methylthien-2-yl)but-3-enyl)-nipecotic acid, in the following referred to by its generic name, tiagabine (INN) and its pharmaceutically active salts has in particular been found useful in the treatment of epilepsy.